Coffee roasting method



Oct. 3, 1967 H. SMITH, JR 3345180 COFFEE ROAS'IING METHOD Filed Jan. 15, 1965 18 Sheets-Sheet l ATTORNEY5' Oct. 3, 1967 H. L. SMITH, JR

COFFEE ROASTING METHOD 18 SheetsShet 2 Fled Jan. 15, 1965 INVENTOR HORACE L. SM/7'H, JR.

BY M7/wf/M ATTORNEY5' OC. 3, 1967 SMITH, JR 3,345,180

COFFEE ROASTING METHOD Filed Jan. 15, 1965 18 Sheets-Sheet 3 INVENTOR HORA 05 L. SMI7'H,JR

ATTORNEYS Oct. 3, 1967 H. 1.. SMITH, JR 3345,180

COFFEE ROASTINGMETHOD F'iled Jan. 15, 1965 18 SheetsSheet 5 INV EN TOR HRA 65 L 5M/ 7'H, JR

BY MVM7M ATTORNEYS Oct. 3, 1967 H. SMITHJJR COFFEE ROASTING METHOD Fled Jan. 15, 1965 18 Sheets-Sheet e INVENTOR ';g"; 1103405 1.. SM/7'H, JR.

ATTORNEYS Oct. 3, 1967 H. L. SMITH, JR

COFFEE ROASTING METHOD Filed Jan. 15, 1965 18 Sheets-Sheet 7 7 INVENTOR HORA 05 L. s/w 7H, JR.

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ATTORNEYS ct. 3, 1967 H. SMITH, JR

COFFEE ROAS'IING METHOD 18 Sheets-Sheet 8 Filed Jan. 15, 1965 INVENTOR Oct. 3, 1967 H. SMITH, JR

COFFEE ROASTING METHD Filed Jan. 15, 1965 18 Sheets-Sheet 9 INVENTO R HORAOE L. SMIT/11 JR.

M7/WM' u Om ct. 3, 1967 SMTH, J 3,345,180

COFFEE ROASTING METHOD Filed Jan. 15, 1965 18 Sheets-Sheet 10 PURGE GAS DISPERSER REACTOR 222 HOT GAS FROM COMMERCIAL N ROASTING UNIT LEGEND A sn.ow VENT ROTARY B LOAD COOLER c praessumze 220 DGEISLATION a ROAST QUICK VENT a UNLOAD UNLOAD OR PURGE COOLER SPRAY MANUAL FLOW ADJUSTMENT (PRESSURIZE) MANUAL FLOW ADJUSTMENT (ROAST) MANUAL FLOW ADJUSTMENT (PURGE) ORIFICE PLATE DRAIN LABORATORY SAMPLE COFFEE ROASTER INVENTOR HRA6E L. SM/7'H, JR

ATTORNEY5 H. L. SMITH, JR

Filed Jan. 15, 1965 18 Sheets-Sheet 12 T START STOF MMTA' .PRESSURIZE s|54 SA L STOP TRT T C L T7 REACTOR s|45 LL MM M' AA START I FF PRESSURE MODULATING A AUTOMATIC PSI PRESSURE SWITCH SET T0 OPEN AT M ALL MANUAL so PSI.

MT T!MED MANUAL T TEMPERATURE CONTROLLED REACTOR INVENTOR HORA6E L SM/7'H, JR.

ATTORNEYS Oct. 3, 1967 L. SM.TH JR 3,345,180

COFFEE ROASTING METHOD Filed Jan. 15, 1965 18 Sheets-Sheet 14 282 w SCRUBBER COMPRESSOR -27e 280 ACCUMULATOR 2 Nll Hllllll I IIIIIII FUEL- REACTOR AIR 1 INVENTOR HOR GE 1.. SMIT/, J/i.

AT'TORNEYS Oct. 3, 1967 H. SMTH, JR

COFFEE ROASTING METHOD 18 Sheets-Sheet 15 Filed Jan. 15, 1965 IN VEN TOR HORAE L. SM/ 7'h', JR

Oct. 3, 1967 H. SMITH, JR

COFFEE ROASTING METHOD Filed Jan. 15, 1965 18 Sheets-Sheet 16 INVENTOR HO/PAGE L SM/Th', JR.

ATTORNEYS H. L. SMITH, JR

Oct. 3, 1967 COFFEE ROASTING METHOD 18 Sheets-Sheet l 7 Filed Jan. 15, 1965 IN V EN TOR HORAGE L. SM/TH, JR.

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A'ITORNEYS United States -at 3,345,180 COFFEE ROASTING METHOD Horace L. Smith, Jr. Richmond, Va. asslguor to Hupp Corporation, Cleveland, 01110, a corporation of Virginia Filet! Jan. 15, 1965, Sar. No. 425,702 25 Claims. (Cl. 99-68) T his invention relates .to novel improved fiuid-solids contact apparatus and to solids t-reating systems employother similar products. It -is to be understood, however,

that the present invention is, in its broader aspects, of far greater utility; and the ensuing discussion of the invention is therefore intended to be illustrative and not limiting With regard to the broader aspects of the invention, which is defined only by the appended claims.

One of the primary objects of the present invention is to provide novel improved methods and apparatus for contacting fluids and solids.

The .foregoing and other important objects of this in-- vention are accomplished by utilizing a novel reaction "vessel which can be pressurized and in which a bed of the solids to be treated is fluidized and continuously rotated 3 during thefluicl treatment cycle. A number of advantages result from fluidizing and contnuously circulating thesolids wbile they are being contacted with the treating fiuid as will become apparent shortly.

Both fluidized beds and beds in which there is a continuous movement. of the solids have heretofore been employe d in apparatus and processes for treating solids with gases and fluids. Exemplary apparatus and processes employing fiudized beds are disclosed in U.S. Patents Nos. 2,212120 issued Aug. 20, 1940, to R. D. Kneale et al. for Methodof Roasting Coifee; 2,857,683 issued Oct. 28, 1958, to F. Schytil for Cofiee Roaster; and 2,859,] 16 issued Nov. 4, 1958, to E. Heimbs et al. for Treatment of Coffee and Other Materials. Exemplary of the patents disclosing apparatus and processes in which there is circulation of the solids being treatd are U.S. Patents Nos. 2,437694 issued Mar. 16, 1948, to C. N. Hickman for Method for Blending Powder Grains; 2689,973 issued Sept. 28, 1954, toL. V. Lee et al. for Method and Apparatus for Contacting Solids with Gases; and 2,78628() issued Mar. 26, 1957, to P. E. Gislrler et al. for Method of Contacting Solid Particles With Fluids and Gcrman Patent No. 1064,789 issued Sept. 3, 1959, to H. Bach tor Tlie term fluirl" is used genorlcnlly hereln to encompusfl gnses, mixtures of guses, and other muterials wlth slmilar iiow proporties.

tlter t vpicnl applicntons of the -prosontinvention include the rousting of otller toodprodncts-such HSCUL'OLI. benns nnd nuts and the munufucture ot' expanded food products such as pui'fed ccreuls and popcorn. Tll present invention rnay also be d'tt'l for dr ving coreul grains or other purticulnte solids und IJr e'iecting a wide vnrioty of chemical reaotions commonly carried out in fluirlized beds. In short, the present invention is applicable to virtunlly nll processen involving the contnot of iiuids with pnrtieulate solids.

"Tho term tiuirtized rotating bed will be omployed to de scriba u bed of solids which is fluidized and in which the solids contimmusly clrculate in puths (shown in FIGURE 7) in wlzicit the solids move upwurtlly in the perlphernl reglons of the. roacion vesscl, inwnrdlv in the upper part of the bed, downwnrtlly in the inner region of the renction vossel, and outm1rdly in the lower part of the bed.

2 Vorrichtung fur Aromaverbesserung und-Stabilisierung von Rstkatee.

The present invention differs from anytlting disclosed in the prior art in that there is bot/z finidization and ro tation of the bed of solids. In addition, the pattern of circulation or rotation ditfers from that which occurs in the prior art processes and apparatris. Specifically, al] of the aboveidentified patents disclosing beds in which there is circulation of the particles are concemed with what are known as spouted beds in which the solids are moved upwardly in a small spout in the center of the bed by the treating fluid and migrate downwardly in the re-maining, major, outer portion of the bed. Ths contrasts directly with the present nvention in which, as mentioned above, the solids move upwardly in the peripheral regions of the bed and downwardly in its inner reaches. In other words, in the fiuidized rotating bed of the present inventon, the particles of solids circulate in a manner directly opposite that to which they crculate in a spouted bed.

The fluidized rotating bed of the present invention has important advantages over both the fluidized and spouted beds of the prior art as was indicated prevously. First, in the present invention, there is a materially more uniform treatment of the solids because of the continuous rapid turnover of the solids in the fluidized rotating bed. In fluidized beds the solids are practically stagnant; and the treating fluid changes eharacteristics (for example, cools) as it passes upwardly through the bed. Consequehtly, the treatment given the solids in the upper part of the bed may vary widely from the treatment of the solids in the lower reaches of the bed; and different particles of the treated product may therefore have radically diterent characteristics.

Solids treated by spouted bed techniques may also contain particles of wdely varying characteristcs becanse there is an extremely slow turnover of the solids due to the sluggish downward migration of the solids in al! but the centra] Spout of a spouted bed. This is because the area of the spout is necessarily very small in comparison to the total area of the bed. As the non-spouted areas of the bed contain a very large part of the solids and as the volume of the solids moving downward in the non spouted part of the bed cannot exceed the volume of solids moving upwardly in the spout whle niuinlaining the s-tability of the bed, the downward migration of the solids is necessarily very slow. Moreover, spouted beds are subject to short-cirouiting. which even further increases non uniformity of the treated product.

A second important advantage of the present invention is that t is much more. versatile than anything bere toforc known ncluding apparutus and processes utlizingfluidized and spoutcd beds. For example, the reaction vessel may be maintuined at pressures varying trom at-mospherlc prcssure (or lcss [ban atmosphcric pressure) to scveral hundred pounds per square inch without up setting the fiuidization or rotation of the bed of solids. Similarly, for a given pressure, the mass rato of flow of the treating dluid can be verried over wide limits without adversely eficcting fluidization or rolation of the solids. Also, other parameters such as the compositiou and tem perature of the treating fiud can be varied as desired for particzular applications without adverse eect.

A third advantage of the present invention over fluidized and spouted bed and other prior art techniques is that the solids treatment can be more accurately controlled becauSe of the intimate and uniform fluid-solids contact provided. This is extremely important in many, if not most, processes utilizing fluid-solids contact.

A further advantage of the present invention in roasting and other applications wbere the solids are heated by the treating tluid is that there is a substantially higher ratc o'f heat transfer from the trcating tluid to the solide than in prior art proeesses and apparatus because of the fluidized rotating bed and because the reaction vessel is pressurized. This matcrially reduees processing time and, therefore, production costs. In addition, in many applications of the present invention, the decreased process time and pressurized fluid treating environment reduce the loss of volatile constituents or otherwise beneficially ctects the solids. Therefore, in many such applications, the tech niques of the present invention provide a treated product which, in comparison to products obtainable by prior art techniques, has materially improved quality or Otl'l6l' im proved characteristics. Analagously, the reduction in process time, treatment ander pressure, and the versatility of the present invention provide materiaily higher yields in many applications of the invention, making the present invention more economical than processes and apparatus utilizing prior art techniques.

Another advantage of the present invention is that power requirements are minimized beoanse there is only a small pressure drop (typicaily less than or slightly above 1.5% of the system pressure) in the treating fluid as it passes through the reaction vessel.

Another important advantage of the present invention is that it aan he .readily cmployed where the particle size of the solids to be treated is too large to be liuidized in the conventional manner.'As pointed out. in the Gishler patent mentioned above, it is extremely difficult to iiuidize partcles having a size greater than 20 mesl:t ann" entircly impracticable to fluidize particles as large as grains of wheat by conventional techniques. By employing the principles of the present invention, however, beds of mach larger particlescotfee beans, for example-can be readily fluidized and rotated.

The present invention also llt1S a further advantageover Spouted bed teehniques in that a mach larger bed of solids can be treated. As a practical matter, a spouted bed cannot be more than a. few inches in diameter. As the width of the bed is increased, the diameter of the spout must be increased or tlte downward migration of die solids in lire non-spouted portions of the bad will be so sluggish as to render the process useless. However, the power required to produce spouting increases much more rapidly than spout diameter; and, if the diameter of the spout is greater than a very few inches, the power required to produce it in other than a shallow bed of no practical utility is economically impracticable. Also, spouts in extremely shallow beds or in beds more than a few inches in diameter are tmstable. This factor makcs it further impracticable to produce spouted beds which are sutficiently large for nse on a commercial scala.

From the foregoing, it will be apparcnt that further important objects of the present invention include the provision of nevel improved fluid-solids contact apparatus and methods:

(1) Which are applicable to a wide variety of processes involving fiuids-solids contact;

(2) In which the bed of solids to be treated is fluidized and continuously rotated by the treating tiuid;

(3) Which are capable of producing a more uniform tinal product and/or a higher quality product or one with botter characteristics than has heretofore been obtainable;

(4) Which are capable of producing a more rapid turnover of the particles being treated than ltas heretoore been possible;

(5) Whiclt are more versatilc than the prior art apparatus for anti methods of producing fluicl-solids contact;

(6) In wlriclr the treatment of the solids aan be more accurately controlled titan has hcretofore been possible;

{7} Which, when the solids are iteated, provide a iiigln au heat transfer trom tlte treating fiuid to the solir en t et0fore employed techniques;

(8) Wt1clr materially reduce tlte time rcquired te eftect a given tn.ament;

(9) Which are capable of handling soiids of larger partiele si2:e liltln thc apparatus anrl processcs of Uw prior art; and

(10) In which it is practicable te treut a larger bed of solide tlllll can be trcntcd l y spoutcd bed and similnr prior art techniqucs.

Another important spcciic object of this present invention is the provision of: nevel improvcd apparatus and methode which incorporatc tl1e novel fluid-solids tech niques discussed above and are particularly adapted tor cotiee roasting and sirniiar applications Roasting cottee by employing the fiuid-solids contact techniques describeci abovc has a number of advantagcs over tl1e proeesses heretotore known. These include increased yields and a roast which is more uniform, has a higher percentage of extractibles (typically on the order of 10% higner), and a higher percentage of total solids in the cup.

The advantage of: increased yields and a more uniform roast are selevidcnt.

The higher percentages of total extractibles is of consderable economie importancc in the mnnufacture of in stant eolee in that the yield ot instant cotlee trom unroasted bcans is a direct rcliection of. the totai ertractibles in the roasteci cotfee. Tnetefore. use of tne present invention dccrcases the cost of producing instant cotfee.

Tlte higher totai solids content providcd by tl:e present invention is also important because the quaiity of brewed eotree is directly related to the total solids content of the roasted beans. Tncretore, collee roasted in accordance with the principles of the present invention makes a better cup of cottce 'tll2lrl tllc same coee roasted by other teclxniques.

Another cxtremeiy important ndvantage of the present invention in the roasting of cotfee is that, because of its versatility and tlte close control over the roasting process t provdes, it materially reduces tlre loss of desirable volatiles and, at the name time, makes it possible to drive oi undesirable volatile components trom lhe beans. As a result, cheap low grade colfees roasted in accord with the present invention can be upgraded to a quality equal to that of expensive bcans roasted by the processes heretofore employed. Consequently, the present invention provides a material economie advantage over both the prior art processes for producing cotiee forgrinding and for producing instant cottce because the major oost factor in produeing cotlec of both types is the cost of the cotee itse'lt.

Another important advantage of roasting coflee in accord with tlte principles of the present invention is that tlte tlcxibility and versatlty of the present invcntion makes it readily adaptable to the roasting of all types of cotiec beans, a versatility which heretofore known proccsses do not possess.

In conjnnction with the foregoing, another important feature of the present invcntion, particularly in cofee roasting and similar applications, is tl1e provision of a cooler inclurlng a nevel timed spray for adding a prede termined amount of water to the roasted product in the form of a fine mist to quench thc roast nnd control the rnoisture content of the roasted product. This provides important advarrtnges over prior art roasting processes in whiclt, as pointed out in U.S. Patent No. 2,278473 issued to /t. Musher Apr. 7', 1942 for Coffee, the water is thrown on the roasted beans whilc they are still in the roaster. Among the more important of these are increased yields, a more uniform product, and longer shelflife.

From the loregoing it will be apparent that futthcr specitic and important oojccts of die present invcntion include the provision of nevel improved coce roasting apparatus ancl Iltiil6ti5, whicit, in contrast te heretofore available techniques:

(l) Produce ncreas-ed yielcis;

(7.) Prodnce a more uniform 1'0ZtSl anti a more uniform final product; 

1. A METHOD OF ROASTING COFFEE BEANS AND SIMILAR PARTICULATE SOLIDS IN A VESSEL HAVING A BED OF THE SOLIDS TO BE ROASTED THEREIN, COMPRISING THE STEPS OF: (A) PRESSURIZING THE ROASTING VESSEL; (B) FLUIDIZING THE BED OF SOLIDS, ROTATING SAID FLUIDIZED BED, AND ROASTING SAID SOLIDS BY EFFECTING A FLOW OF HEATED FLUID INTO SAID BED; (C) CONCURRENTLY TERMINATING THE FLOW OF HEATED FLUID INTO THE BED OF SOLIDS AND REDUCING THE PRESSURE IN SAID VESSEL TO A PRESSURE SUBSTANTIALLY ABOVE ATMOSPHERIC BEFORE SAID SOLIDS ARE COMPLETELY ROASTED; AND 